[BUG] WebFetch tool unable to access any external documentation sites

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When attempting to use the WebFetch tool to access external documentation sites, Claude Code consistently returns errors indicating it cannot fetch from any external domains. This severely limits the tool's ability to provide accurate, up-to-date information from official documentation sources.

The command fails immediately with the error message: Claude Code is unable to fetch from [domain] for all tested sites.

What Should Happen?

Claude Code should successfully fetch content from common documentation sites and technical resources needed for software development tasks, particularly:

• Official Claude Code documentation (docs.claude.com)
• Programming language documentation (docs.oracle.com, developer.mozilla.org)
• Code repositories (github.com)

Error Messages/Logs

Steps to Reproduce

1. Start a Claude Code session
2. Request information that requires fetching external documentation:

User: "Can you check the Claude Code documentation about model settings?"

1. Claude Code attempts to use WebFetch tool:

WebFetch(url="https://docs.claude.com/en/docs/claude-code/configuration")

1. Error appears: "Claude Code is unable to fetch from docs.claude.com"

Note: This issue occurs with ALL external websites, not just Claude's documentation.

Error Messages/Logs

<function_results>
<error>Claude Code is unable to fetch from docs.claude.com</error>
</function_results>

<function_results>
<error>Claude Code is unable to fetch from docs.oracle.com</error>
</function_results>

<function_results>
<error>Claude Code is unable to fetch from developer.mozilla.org</error>
</function_results>

<function_results>
<error>Claude Code is unable to fetch from github.com</error>
</function_results>

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

1.0.127 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

IntelliJ IDEA terminal

Additional Information

model: Claude Opus 4.1 (claude-opus-4-1-20250805)